1. Field of the Invention
The present invention relates to a reciprocating-type cutting device that has first and second driving bodies formed by a pair of plate-like bodies which are superposed in a thickness direction and reciprocatingly driven in opposite directions by a predetermined driving mechanism, first and second cutting blade bodies formed by a pair of plate-like bodies which are integrally reciprocatingly driven by detachably engaging with non-drive ends of the first and second driving bodies and which have cutting blades having a predetermined shape on lateral edges thereof, and a pair of detachable guide plates which are disposed on both sides of the cutting bodies and driving bodies in the thickness direction so as to hold the cutting bodies and driving bodies slidably.
2. Description of the Related Art
Reciprocating-type cutting blade devices which are used in mowing machines and pruning machines, such as the device disclosed in Japanese Unexamined Patent Publication No. 8-172838 below, for example, are conventionally known. An example of such a device is shown in FIG. 21. A reciprocating-type cutting blade device 200 as shown in FIG. 21 comprises an upper guide plate 201, the base end (the end on the right side of the figure) of which is connected to a mission case (not illustrated), a lower guide plate 202, which is detachably connected to the lower side of the upper guide plate 201, an upper cutting blade body 203 and a lower cutting blade body 204, which are held from both sides between the guide plates 201 and 202 so as to be capable of sliding reciprocatingly therebetween in a longitudinal direction, and an upper driving member 207 and a lower driving member 208 which are reciprocatingly driven in mutually opposite directions by a driving mechanism (not illustrated) that is provided in the mission case. Furthermore, the configuration is such that detachable engagement of respective tips (tips on the non-drive side) of the driving members 207 and 208 with the base ends of the cutting blade bodies 203 and 204 causes the cutting blade bodies 203 and 204 to be reciprocatingly driven integrally with the driving members 207 and 208 in the longitudinal direction.
More specifically, in the example of FIG. 21, keyblade-like connecting parts 203a and 204a having a stepped portion in the width direction are formed at the base ends of the upper cutting blade body 203 and lower cutting blade body 204 respectively, keyblade-like connecting parts 207a and 208a which have a stepped portion in the width direction and which are connected to the connecting parts 203a and 204a by being inserted therein from above or below are formed at the tips of the upper driving member 207 and the lower driving member 208, and the cutting blade bodies 203 and 204 and driving members 207 and 208 are detachably engaged with one another via the connecting parts 203a, 204a, 207a, and 208a respectively.
In the configuration disclosed in Patent Document 1, when the upper cutting blade body 203 and lower cutting blade body 204 are removed, a bolt or the like that connects the upper guide plate 201 and the lower guide plate 202 to each other is first released, and then the lower guide plate 202 is separated from the upper guide plate 201 that is connected to the mission case (not illustrated). If the upper cutting blade body 203 and lower cutting blade body 204 are moved above or below with respect to the driving members 207 and 208 in this state, the cutting blade bodies 203 and 204 can be easily removed from the driving members 207 and 208. Hence, with the configuration of Japanese Unexamined Patent Publication No. 8-172838, there is the advantage that the detachability of the cutting blade bodies 203 and 204 can be improved and maintenance work such as re-grinding the teeth 203b and 204b can be easily performed.
Furthermore, in the abovementioned Japanese Unexamined Patent Publication No. 8-172838, since no particular difference in shape is described between the connecting part 203a of the upper cutting blade body 203 (or the connecting part 207a of the upper driving member 207) and the connecting part 204a of the lower cutting blade body 204 (or the connecting part 208a of the lower driving member 208), these connecting parts are considered to be the same shape. Hence, assuming that the boundary formed between the connecting parts 203a and 207a of the upper cutting blade body 203 and the upper driving member 207 is Q201 and that the boundary formed between the connecting parts 204a and 208a of the lower cutting blade body 204 and the lower driving member 208 is Q202, the boundaries Q201 and Q202 must, in a planar view, coincide with each other once (FIG. 22B) while the cutting blade bodies 203 and 204 make a single stroke, as shown in FIGS. 22A to 22C. Note that, in FIGS. 22A to 22C, the upper cutting blade body 203 and the upper driving member 207 are each denoted by a bold dot-chain line, while the lower cutting blade body 204 and the lower driving member 208 are each denoted by a narrow broken line. Furthermore, when the two boundaries Q201 and Q202 coincide in a planar view as shown in FIG. 22B, there is a risk of interference between steps existing along the boundaries Q201 and Q202, thereby impeding the smooth reciprocating motion of the cutting blade bodies 203 and 204.
In other words, since there is normally a discrepancy owing to dimensional tolerance during manufacture between the thickness dimension of the cutting blade bodies 203 and 204 and the thickness dimension of the driving members 207 and 208, a step is generated by this dimensional tolerance for each of the boundaries Q201 and Q202. Furthermore, if such steps are generated, when the boundaries Q201 and Q202 coincide in a planar view, there is a risk of the steps making contact with each other (interfering each other) due to line contact therebetween, and of the reciprocating motion of the cutting blade bodies 203 and 204 being impeded.